tryflag () {
printf "checking whether compiler accepts %s... " "$2"
echo "typedef int x;" > "$tmpc"
-if $CC $2 -c -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
+if $CC $CFLAGS_TRY $2 -c -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
printf "yes\n"
eval "$1=\"\${$1} \$2\""
eval "$1=\${$1# }"
tryldflag () {
printf "checking whether linker accepts %s... " "$2"
echo "typedef int x;" > "$tmpc"
-if $CC -nostdlib -shared "$2" -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
+if $CC $LDFLAGS_TRY -nostdlib -shared "$2" -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
printf "yes\n"
eval "$1=\"\${$1} \$2\""
eval "$1=\${$1# }"
CFLAGS_AUTO=
CFLAGS_MEMOPS=
CFLAGS_NOSSP=
+CFLAGS_TRY=
LDFLAGS_AUTO=
+LDFLAGS_TRY=
OPTIMIZE_GLOBS=
prefix=/usr/local/musl
exec_prefix='$(prefix)'
fi
#
+# Figure out options to force errors on unknown flags.
+#
+tryflag CFLAGS_TRY -Werror=unknown-warning-option
+tryflag CFLAGS_TRY -Werror=unused-command-line-argument
+tryldflag LDFLAGS_TRY -Werror=unknown-warning-option
+tryldflag LDFLAGS_TRY -Werror=unused-command-line-argument
+
+#
# Need to know if the compiler is gcc to decide whether to build the
# musl-gcc wrapper, and for critical bug detection in some gcc versions.
#